Centralize canvas progress teardown

docs/modernization/debt.md

@@ -561,6 +561,11 @@ agent or engineer to remove them without reconstructing context from chat.
   helpers in `src/legacy_ui_overlay_services.*`. Floating-panel dock/drop
   reparenting still uses legacy child-vector ownership until checked handles
   land.
+- 2026-06-12: DEBT-0063/DEBT-0058 were narrowed again. Canvas export/project
+  progress-bar cleanup and remote-page loading placeholder cleanup now route
+  through retained close/destroy helpers in `src/legacy_ui_overlay_services.*`.
+  The long-running canvas workflows still depend on legacy `App::I` UI tasking
+  and raw progress-bar pointers.
 - 2026-06-05: DEBT-0011 was narrowed. The Windows app package smoke target now
   passes the configure-time CMake executable into `package-smoke.ps1`, so VS
   2026 generator validation does not depend on an older `cmake` on PATH, and

docs/modernization/roadmap.md

@@ -524,6 +524,8 @@ recovery message dialogs now route through the retained dialog close helper.
 Floating-panel placeholder detach/destroy, cloud-loading alignment cleanup,
 brush-preset item removal, and retained popup-panel parent detach now use named
 retained node helpers; dock/drop reparenting remains legacy-owned.
+Canvas export/project progress-bar cleanup and remote-page loading placeholder
+cleanup now route through those same retained close/destroy helpers.
 Raw popup callback captures and full close/capture ownership remain part of
 `DEBT-0063`.
 `pano_cli inspect-image` exposes PNG IHDR metadata as JSON,